Washington Co., WI – Your bluebird box was meant to invite bluebirds to your property, but suddenly you’re seeing other birds checking it out, perhaps moving in. Don’t be too hasty to remove other birds. You may be breaking the law.
Several other cavity nesters/ songbirds will also find your nest box to their liking. Let’s find out who to welcome and who should “get the boot.”
Chickadee nests are short and made of grasses, animal hair and moss. First-year birds may lay the eggs right by the door, so always open your box slowly and carefully. You may move the eggs toward the center of the nest. Birds cannot smell, so your scent will not keep them from returning to the nest. Chickadee eggs are quite small. They are white with brown to reddish-brown specks.
Tree Swallow males and females look much the same. They have blue-black backs and white chests and bellies.
As you approach a box with tree swallows, one or more may swoop down to scare you away. They will not strike you if you stay calm and talk quietly to them. If you are monitoring your boxes for an organization like BRAW (Bluebird Restoration Association of WI), look quickly and move away to fill out the paperwork.
Tree swallow nests are made of coarser grass and straw, then lined with feathers when the white eggs are laid. The feathers may be from local chickens.
The nest is large and made of twigs, sometimes twigs with thorns. If you are monitoring your boxes for an organization like BRAW, you’ll want to be careful of the thorns. Deep inside the twigs toward the bottom of the box will be a small grass nest in active boxes. Males come early, setting up multiple nests for prospective females. Females select only one box. If your box with twigs does not have a grass nest after two weeks of checking, it is a “dummy” box. You may remove the twigs to a place far from the nest box. Dropping the twigs below the box will attract raccoons and other animals who may later rob the nests. Eggs are quite small and reddish.
Bluebirds, chickadees, tree swallows, and wrens are all protected song-birds. Their nests can only be removed from boxes after eggs hatch. “Dummy” wren nests may be removed after 3 weeks with no grass nest inside at the bottom of the twigs.
This publication is produced by Master Gardner Volunteers of the University of Wisconsin Extension-Washington County. Contact the Washington Co. UW-Extension office: www.facebook.com/wcwimastergardeners